The IIC routines act as master. The application currently interrogates an ADC chip and writes information to a LCD display (which is not IIC). I would now like to change the IIC routine to act as a slave. Why? I will be interfacing the device with another device (via the externalized IIC interface) that will act as the master. The new external device will interrogate the ADC (via IIC) and then send information to the application running on the MC9S08QG8) (acting as slave). The application will then update the LCD display. So, the bottom line is I would like the current MC9S08QG8 application to act as a slave.

I suggest you to use the AN3291 as the first step how to set-up and use the IIC module on S08QG8 as a slave. The slave must work in the interrupt routine, to be able promptly communicate with master IIC device. The SW examples in this AN are in clear C, so you can use it in your version of CW tool. Here is the link: